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Air Quality

Regulation and SIP Management

State Implementation Plan

The State Implementation Plan (SIP) is developed to show how a state will meet the National Ambient Air Quality Standards (NAAQS) for six common pollutants, called "criteria pollutants," as set forth by the Clean Air Act.

A SIP is the accumulated record of many documents that form a blueprint and timeline for the state's plans to assure compliance with the NAAQS for criteria pollutants (carbon monoxide, sulfur dioxide, ozone, nitrogen dioxide, lead, and particulate matter), as outlined in the Clean Air Act. SIPs include, among other things, control plans, regulations, inventories of emissions within the state, and transcripts of public involvement in the SIP-development process. Once approved, the SIP is enforceable by the state and EPA. Elements of South Carolina's SIP have been in place since 1972. Though there have been many amendments, there is only one South Carolina SIP. For more information, see EPA's SIP webpage.

Infrastructure State Implementation Plan (SIP)

Sections 110(a)(1) and (2) of the Clean Air Act require all states to submit plan elements to provide for the implementation, maintenance, and enforcement of the NAAQS. Sections 110(a)(1) and (2) further require states to address basic SIP requirements, including but not limited to the following elements: emissions limits and other control measures, ambient air quality monitoring, a program for the enforcement of control measures, adequate resources to implement the SIP, and public notification and government consultation. These elements are commonly called "infrastructure" elements of the SIP. Section 110(a) requires states to submit SIP revisions within three (3) years after promulgation of a new or revised NAAQS. These SIP amendments essentially certify to EPA that the state has the elements in place to allow it to continue to maintain the NAAQS.

The first NAAQS for which EPA required an infrastructure SIP certification was the 1997 Ozone NAAQS. EPA has since required infrastructure SIPs for NAAQS that have been revised.

For more information on Infrastructure SIP certifications, see EPA's Infrastructure SIP webpage.

DHEC has submitted the following Infrastructure SIP certifications for approval:


For more information please contact the Bureau of Air Quality at (803) 898-4123 or by email.